Beginning of Creation

Bukhari :: Book 4 :: Volume 54 :: Hadith 419

Narrated Abu Bakra:

The Prophet said. "(The division of time has turned to its
original form which was current when Allah created the Heavens and
the Earths. The year is of twelve months, out of which four months
are sacred: Three are in succession Dhul-Qa' da, Dhul-Hijja and
Muharram, and (the fourth is) Rajab of (the tribe of) Mudar which
comes between Jumadi-ath-Thaniyah and Sha ban."